Low-cycle fatigue test tool and method for bolted connection wheel disc

Abstract

The invention discloses a low-cycle fatigue test tool and method for a bolted connection wheel disc in the technical field of test tools, and the tool is connected with a mounting edge and a switching part of the wheel disc through a base plate, and the base plate is in interference fit with the mounting edge and the switching part of the wheel disc. The first bending moment jointly generated by the wheel disc mounting edge and the first spigot is balanced through the second bending moment generated by the second spigot during the test, and the wrapping level of the first spigot on the wheel disc mounting edge is adjusted, so that the stress level of the bolt hole part on the wheel disc during the low-cycle fatigue test is controlled, and finally, the bolt hole part on the wheel disc is accurately assessed; the size of the base plate is smaller, the time needed for heating during replacement is shorter, the production cost is lower, fatigue dangerous points are concentrated on the base plate with the smaller size, only the base plate needs to be replaced in the test process, and the test time and the test cost can be saved.

Description

Technical Field

[0001] The invention relates to the technical field of test fixtures, and in particular to a low-cycle fatigue test fixture and method for a bolt-connected wheel disc. Background Art

[0002] As aircraft engines continue to pursue higher performance and longer life, the structure and assessment of the wheel disc are becoming more and more complex. At very high test speeds and test temperatures, the test needs to simulate the stress and stress distribution of the key parts of the wheel disc under working conditions. At the same time, the test fixture must have a long enough low-cycle fatigue life to ensure that it does not fail before the test piece, which makes the test very difficult.

[0003] The detachable compressor rotor and turbine rotor are generally connected by bolts, and the local force of the bolt hole is complex. In order to realize the low-cycle fatigue test assessment of the position of the wheel bolt hole, there are multiple fatigue risk points in the test fixture, which will inevitably lead to a reduction in the low-cycle fatigue life of the test fixture. It is necessary to process multiple test fixtures to complete the assessment of the wheel.

[0004] The existing aircraft engine bolt connection wheel test tooling usually adopts the following Figure 1 The structure shown in the figure. A shaft with an inner stop is used to center the outer stop cylindrical surface of the wheel disc, and a circle of bolts is used to tighten it. The function of the counterweight hole is to perform low-speed dynamic balancing by adding screws to reduce vibration during the test. The test fixture can simultaneously test the wheel center and the wheel bolt hole. Finite element analysis revealed that due to the large radial deformation of the outer stop of the wheel disc, the radial contact force generated was very large, causing the shaft stop to bend to the right, and the left side of the shaft was subjected to the superposition of bending tensile stress and centrifugal tensile stress. Therefore, the fatigue danger points were at the chamfer of the stop, the left side of the bolt hole, and the left side of the counterweight hole. The low-cycle fatigue life of the chamfer of the stop and the counterweight hole was very low. Since the test fixture cannot be destroyed before the wheel disc, in order to complete the low-cycle fatigue life assessment of the wheel disc, the test fixture shaft needs to be processed with multiple spare parts and replaced in the middle of the test, which is costly. Moreover, since the stop is an interference fit, the test fixture shaft needs to be heated and inserted into the outer stop of the wheel disc, and the nut needs to be tightened after it cools to room temperature. Due to the large volume of the shaft, it takes about 1 hour to heat up and about 4 hours to cool down, and the assembly efficiency is very low.

[0005] Based on this, the present invention designs a low-cycle fatigue test tool and method for a bolt-connected wheel disc to solve the above-mentioned problem. Summary of the invention

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a low-cycle fatigue test tool for a bolt-connected wheel disc, which is used to perform a low-cycle fatigue test on a bolt hole portion on a wheel disc, and comprises a driving member, an adapter and a pad, wherein the two axial ends of the adapter are respectively a first end and a second end, the wheel disc is mounted on the first end of the adapter through the pad, and the second end of the adapter is used to connect the driving member so as to output torque to the adapter through the driving member; the two axial ends of the pad are respectively provided with a first stop and a second stop, the inner diameter of the first stop matches the diameter of the mounting edge of the wheel disc for interference fit with the mounting edge of the wheel disc, and the inner diameter of the second stop matches the diameter of the first end of the adapter for interference fit with the first end of the adapter; the pad and the first end of the adapter are both provided with bolt hole portions corresponding to the positions of the bolt hole portions on the wheel disc, so that the bolt installation can perform a low-cycle fatigue test on the bolt hole portions opened on the mounting edge of the wheel disc.

[0007] As a further solution of the present invention, the axial height of the second stop is obtained by finite element analysis, and the specific steps are as follows: S11, finite element model establishment; Establish a finite element model of the adapter, the pad and the wheel, and set the initial axial height of the second stop; S12, structural finite element analysis; Apply centrifugal load and temperature load to the established finite element model to simulate the test state and analyze the stress level of the bolt hole on the wheel disc; S13, stress level result analysis; If the stress level of the bolt hole on the wheel disc is lower than the stress level of the bolt hole on the wheel disc when the engine is in operation, it is determined that the bolt hole on the wheel disc is under-tested, the axial height of the second stop is reduced, and the process returns to step S12; If the stress level of the bolt hole on the wheel disc is greater than the stress level of the bolt hole on the wheel disc when the engine is in operation, it is determined that the bolt hole on the wheel disc has passed the test, the axial height of the second stop is increased, and the process returns to step S12; If the stress level of the bolt hole on the wheel disc is consistent with the stress level of the bolt hole on the wheel disc when the engine is in working condition, it is determined that the current stress level of the bolt hole on the wheel disc is qualified, and the current result is output.

[0008] As a further solution of the present invention, in step S13, if it is determined that the bolt hole position on the current wheel disc is under-tested, the interference amount can be reduced based on the initial value of the interference amount between the second stop and the first end of the transition portion; if it is determined that the bolt hole position on the current wheel disc is over-tested, the interference amount can be increased based on the initial value of the interference amount between the second stop and the first end of the transition portion.

[0009] As a further solution of the present invention, a first truncated cone is provided on one side of the gasket where the first stop is provided. The diameter of the first truncated cone is smaller than the inner diameter of the wheel disc mounting edge and there is a smooth transition between the edge and the gasket.

[0010] As a further solution of the present invention, a second cone is provided on one side of the pad where the second stop is provided, the radius of the second cone is smaller than the distance from the bolt hole on the pad to the center axis of the pad and there is a smooth transition between the edge and the pad, and a clearance groove for making way for the second cone is provided on the end face of the first end of the transition part.

[0011] As a further solution of the present invention, the end faces at both ends of the gasket in the axial direction are respectively provided with an annular first transition groove and a second transition groove, the first transition groove and the first stop are located on the same end face of the gasket and the outer edge of the first transition groove is adjacent to the inner ring surface of the first stop, the second transition groove and the second stop are located on the same end face of the gasket and the outer edge of the second transition groove is adjacent to the inner ring surface of the second stop, so as to smoothly transition the connection between the first stop and the second stop and the gasket.

[0012] As a further solution of the present invention, the cross-sections of the first transition groove and the second transition groove are both semicircular.

[0013] As a further solution of the present invention, the transition portion is divided into a first section, a second section and a third section from the second end to the first end, the diameters of the first section, the second section and the third section increase successively, and the axial height of the third section is smaller than the axial height of the pad.

[0014] As a further solution of the present invention, a counterweight hole is opened in the second section of the adapter portion.

[0015] As a further solution of the present invention, a method for low cycle fatigue testing of a bolted wheel disc is provided, which is applicable to a low cycle fatigue testing tool for a bolted wheel disc, and comprises the following steps: S21, wheel assembly; Heat the backing plate to a set temperature, then fit the installation edge of the wheel disc into the first stop, fit the first end of the adapter into the second stop, and align the bolt holes of the wheel disc installation edge, the backing plate, and the first end of the adapter; S22, bolt installation; After the backing plate cools down, the bolts are passed through the wheel disc mounting edge, the backing plate and the bolt holes opened at the first end of the adapter, and the nuts are assembled and tightened; S23, test assessment; The second end of the adapter is fixedly connected to the driving member, and torque is applied to the adapter through the driving member to make the wheel disc, the pad and the adapter rotate according to the set upper and lower limit speed spectrum. At the same time, the wheel disc is heated to the set temperature by the heating device, and the pad is replaced regularly according to the fatigue life of the pad until the bolt hole of the wheel disc reaches the target fatigue life or reaches the fatigue limit rupture.

[0016] The present invention has the following beneficial effects: The present invention connects the mounting edge and the adapter of the wheel disc through a pad, and the pad, the mounting edge and the adapter of the wheel disc are all interference fit. The first bending moment jointly generated by the mounting edge of the wheel disc and the first stop is balanced by the second bending moment generated by the second stop during the test, and the wrapping level of the first stop on the mounting edge of the wheel disc is adjusted, so as to control the stress level of the bolt hole position on the wheel disc during the low cycle fatigue test, and finally accurately assess the bolt hole position on the wheel disc. At the same time, the pad is smaller in size, the time required for heating during replacement is shorter, and the cost during production is also lower. The fatigue risk points are concentrated on the pad with a smaller volume. During the test, only the pad needs to be replaced, which can save test time and test cost.

[0017] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 This is a schematic diagram of the structure of the prior art; Figure 2 Schematic diagram of the overall structure of the present invention; Figure 3 It is a schematic diagram of the enlarged structure of the present invention.

[0019] Legend: 1. Driving member; 2. Adapter; 3. Bolt; 4. Nut; 5. Wheel; 6. Pad; 61. First stopper; 62. Second stopper; 63. First truncated cone; 64. Second truncated cone; 65. First transition groove; 66. Second transition groove. DETAILED DESCRIPTION

[0020] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0021] See also Figure 1-Figure 3 The present invention provides a technical solution: a bolt-connected wheel disc low-cycle fatigue test fixture, which is used to perform a low-cycle fatigue test on the bolt hole portion of the wheel disc 5, comprising a driving member 1, an adapter 2 and a pad 6, wherein the two ends of the adapter 2 in the axial direction are respectively a first end and a second end, the wheel disc 5 is installed on the first end of the adapter 2 through the pad 6, and the second end of the adapter 2 is used to connect the driving member 1 to output torque to the adapter 2 through the driving member 1; The two ends of the backing plate 6 in the axial direction are respectively provided with a first stopper 61 and a second stopper 62. The inner diameter of the first stopper 61 matches the diameter of the mounting edge of the wheel disc 5 for interference fit with the mounting edge of the wheel disc 5. The inner diameter of the second stopper 62 matches the diameter of the first end of the adapter 2 for interference fit with the first end of the adapter 2. The backing plate 6 and the first end of the adapter 2 are both provided with bolt hole portions corresponding to the bolt hole portions on the wheel disc 5 for the bolt 3 to be installed to perform a low cycle fatigue test on the bolt hole portions on the wheel disc 5 .

[0022] During the test, the wheel disc 5 is assembled to the first end of the adapter 2 through the pad 6, and the second end of the adapter 2 is connected to the driving member 1. The driving member 1 is started to drive the adapter 2 and the wheel disc 5 to rotate, so as to simulate the centrifugal load on the wheel disc 5 when working, and a low-cycle fatigue test is performed on the bolt hole part of the wheel disc 5. During the test, the installation edge of the wheel disc 5 generates a large radial contact force on the inner side of the first stop 61 under the action of centrifugal force, so that the first stop 61 is simultaneously subjected to the bending tensile stress of the installation edge of the wheel disc 5 and the centrifugal tensile stress, which will generate a first bending moment to the right on the pad 6, and the second stop 62 is also subjected to the centrifugal force. Centrifugal tensile stress, the centrifugal tensile stress on the second stop 62 will generate a second bending moment to the left on the pad 6, so as to balance the first bending moment through the second bending moment to reduce the first bending moment. By controlling the axial length of the second stop 62, the size of the second bending moment during the test can be adjusted, thereby controlling the size of the first bending moment, and adjusting the wrapping level of the first stop 61 on the installation edge of the wheel disc 5, so as to control the stress level of the bolt hole part on the wheel disc 5 during the low cycle fatigue test, so that the stress level of the bolt hole part on the wheel disc 5 during the low cycle fatigue test is closer to the actual state, so as to achieve a more accurate assessment of the bolt hole part on the wheel disc 5; Moreover, during the test, the first bending moment is greater than the second bending moment, and the first bending moment acts on the first end of the adapter 2 through the second stop 62. At this time, the first end of the adapter 2 is subjected to compressive stress. According to the principle of stress superposition, the superposition of tensile stress and centrifugal tensile stress will increase the stress, and the superposition of compressive stress and centrifugal tensile stress will reduce the stress. In this way, the stress level of the adapter 2 can be reduced, so that the stress amplitude of the bolt hole part opened on the adapter 2 is greatly reduced, and the low-cycle fatigue life is significantly improved. Since the adapter 2 needs to be connected to the driving member 1 and the moment of inertia needs to meet certain requirements, the volume cannot be further reduced, and replacement is very time-consuming and the manufacturing cost is high. Therefore, the low-cycle fatigue life of the bolt hole part opened on the adapter 2 is improved, which can reduce the test cost. The volume of the pad 6 is much smaller than that of the adapter 2, and the time required for heating during replacement is shorter, and the cost during production is also lower. The fatigue risk points are concentrated on the pad 6 with a smaller volume. During the test, only the pad 6 needs to be replaced, which can save test time and test cost. The present invention connects the mounting edge of the wheel disc 5 and the adapter 2 through the pad 6, and the pad 6 and the mounting edge of the wheel disc 5 and the adapter 2 are all interference fit. The first bending moment generated by the mounting edge of the wheel disc 5 and the first stop 61 is balanced by the second bending moment generated by the second stop 62 during the test, and the wrapping level of the first stop 61 on the mounting edge of the wheel disc 5 is adjusted, so as to control the stress level of the bolt hole part on the wheel disc 5 during the low cycle fatigue test, and finally accurately assess the bolt hole part on the wheel disc 5. At the same time, the pad 6 is smaller in size, the time required for heating during replacement is shorter, and the cost during production is also lower. The fatigue risk point is concentrated on the pad 6 with a smaller volume. During the test, only the pad 6 needs to be replaced, which can save test time and test cost. like Figure 1 As shown, in the prior art, the stopper of the adapter 2 for mounting the wheel disc 5 is a fatigue risk point A, the bolt hole on the adapter 2 is a fatigue risk point B, and the counterweight hole on the adapter 2 is a fatigue risk point C; like Figure 2 As shown, in this solution, the first stop 61 on the backing plate 6 is the fatigue risk point F, the bolt hole on the backing plate 6 is the fatigue risk point G, and the bolt hole on the adapter 2 is the fatigue risk point B. It can be seen that there is only one fatigue risk point on the adapter 2, and the number of fatigue risk points on the adapter 2 is reduced, which can effectively increase the fatigue life of the adapter 2; Figure 1-Figure 2 In the figure, the wheel center of the wheel disc 5 is the test part E, and the bolt hole on the wheel disc 5 is the test part D.

[0023] Specifically, the axial height of the second stop 62 is obtained by finite element analysis, and the specific steps are as follows: S11, finite element model establishment; Establish a finite element model of the adapter 2, the pad 6 and the wheel 5, and arbitrarily set the initial axial height of the second stop 62. The axial height of the second stop 62 can be set within a reasonable range based on past experience; S12, structural finite element analysis; Apply centrifugal load and temperature load to the established finite element model to simulate the test state, analyze the stress level of the bolt hole on the wheel disc 5, and obtain the stress level of the bolt hole on the wheel disc 5 at the axial height of the initial second stop 62 by simulating the test state in the finite element analysis software; S13, stress level result analysis; After obtaining the stress level of the bolt hole portion on the wheel disc 5 under the condition of the initial axial height of the second stop 62, the obtained stress level of the bolt hole is compared with the stress level of the bolt hole portion on the wheel disc 5 under the engine working state, and the difference between the current stress level of the bolt hole portion on the wheel disc 5 and the stress level under the engine working state is obtained, and the height of the second stop 62 is adjusted according to the difference value; If the stress level of the bolt hole on the wheel disc 5 is less than the stress level of the bolt hole on the wheel disc 5 when the engine is in operation, it means that the pressure of the first stop 61 on the installation side of the wheel disc 5 is too large, resulting in too low stress level of the bolt hole on the wheel disc 5, so that the bolt hole on the wheel disc 5 is not tested. At this time, the axial height of the second stop 62 needs to be reduced, so as to reduce the magnitude of the second bending moment during the test, and finally reduce the pressure of the first stop 61 on the installation side of the wheel disc 5, increase the stress level of the bolt hole on the wheel disc 5 and return to step S12; If the stress level of the bolt hole on the wheel disc 5 is greater than the stress level of the bolt hole on the wheel disc 5 when the engine is in operation, it means that the pressure of the first stop 61 on the installation side of the wheel disc 5 is too small, resulting in too high stress level of the bolt hole on the wheel disc 5, so that the bolt hole on the wheel disc 5 currently passes the test. At this time, the axial height of the second stop 62 is increased, thereby increasing the magnitude of the second bending moment during the test, and finally increasing the pressure of the first stop 61 on the installation side of the wheel disc 5, reducing the stress level of the bolt hole on the wheel disc 5, and returning to step S12; If the stress level of the bolt hole on the wheel disc 5 is consistent with the stress level of the bolt hole on the wheel disc 5 under the working state of the engine, it is determined that the stress level of the bolt hole on the wheel disc 5 is qualified, and the current result is output. The pad 6 is produced using the current output result, and then the low cycle fatigue test of the wheel disc 5 is carried out; The stress level of the bolt hole on the wheel disc 5 during the test is simulated by finite element analysis software, and the obtained stress level is compared with the stress level under the working state of the engine to determine whether the bolt hole on the current wheel disc 5 is under-assessed, over-assessed or just meets the requirements. Based on the comparison result, it is determined whether the axial height of the current second stop 62 needs to be adjusted and how to adjust it. After the axial height of the second stop 62 is adjusted, finite element analysis is performed again until the stress level of the bolt hole on the wheel disc 5 during the test is consistent with the stress level under the working state of the engine, so as to ensure that the bolt hole on the wheel disc 5 can be accurately assessed.

[0024] Further, in step S13, if it is determined that the bolt hole position on the current wheel disc 5 is under-tested, the interference amount can be reduced from the initial value of the interference amount between the second stop 62 and the first end of the adapter 2; if it is determined that the bolt hole position on the current wheel disc 5 is over-tested, the interference amount can be increased from the initial value of the interference amount between the second stop 62 and the first end of the adapter 2; The height of the second stop 62 is adjusted to control the second bending moment, thereby adjusting the wrapping level of the first stop 61 on the installation edge of the wheel disc 5. Therefore, the same effect can be achieved by adjusting the interference between the second stop 62 and the first end of the adapter 2. When the finite element model is established in step S11, the initial interference between the second stop 62 and the first end of the adapter 2 is set. In step S13, if it is determined that the bolt hole position on the current wheel disc 5 is not tested, it means that the wrapping force of the first stop 61 on the installation edge of the wheel disc 5 is too large during the test, resulting in too small stress level at the bolt hole position on the wheel disc 5 at the test speed. At this time, it is necessary to reduce the wrapping force of the first stop 61 on the installation edge of the wheel disc 5, and reducing the interference between the second stop 62 and the first end of the adapter 2 can also reduce the second bending moment, thereby reducing the balance of the second bending moment to the first bending moment, and finally reducing the wrapping level of the first stop 61 on the installation edge of the wheel disc 5, and increasing the stress level of the bolt hole position on the wheel disc 5 during the test; In step S13, if it is determined that the bolt hole position on the current wheel disc 5 has passed the test, it means that the wrapping force of the first stop 61 on the mounting edge of the wheel disc 5 during the test is too small, resulting in excessive stress level at the bolt hole position on the wheel disc 5 at the test speed. At this time, it is necessary to increase the wrapping force of the first stop 61 on the mounting edge of the wheel disc 5, and increasing the interference fit between the second stop 62 and the first end of the adapter 2 can also increase the second bending moment, thereby increasing the balance of the second bending moment to the first bending moment, and finally increasing the wrapping level of the first stop 61 on the mounting edge of the wheel disc 5, reducing the stress level of the bolt hole position on the wheel disc 5 during the test, and providing a variety of feasible methods for adjusting the stress level of the bolt hole position on the wheel disc 5.

[0025] Further, such as Figure 3 As shown, the side of the backing plate 6 where the first stop 61 is provided is provided with a first truncated cone 63, and the side where the second stop 62 is provided is provided with a second truncated cone 64, so as to increase the thickness of the center of the backing plate 6, which is beneficial to improve the ability of the backing plate 6 to bear centrifugal loads and axial bending loads, improve its low cycle fatigue life, and thus reduce the test risk; Specifically, the diameter of the first cone 63 is smaller than the inner diameter of the mounting edge of the wheel disc 5, and the radius of the second cone 64 is smaller than the distance from the bolt hole on the pad 6 to the central axis of the pad 6. Since the length of the bolts 3 used to connect the wheel disc 5, the pad 6 and the adapter 2 is fixed, the first cone 63 and the second cone 64 need to avoid the bolt holes opened on the pad 6, thereby further increasing the thickness of the central area of ​​the pad 6 on the maximum thickness that the pad 6 can reach.

[0026] Specifically, the edges of the first truncated cone 63 and the second truncated cone 64 are smoothly transitioned from the pad 6 to reduce the stress concentration at the edges of the first truncated cone 63 and the second truncated cone 64, thereby reducing the test risk; Specifically, a groove for accommodating the second truncated platform 64 is formed on the end surface of the first end of the adapter portion 2 , thereby providing space for the second truncated platform 64 .

[0027] Further, such as Figure 3 As shown, the end surfaces at both ends of the backing plate 6 in the axial direction are respectively provided with an annular first transition groove 65 and a second transition groove 66, the first transition groove 65 and the first stop 61 are located at the same end surface of the backing plate 6, and the outer edge of the first transition groove 65 is adjacent to the inner annular surface of the first stop 61, and the second transition groove 66 and the second stop 62 are located at the same end surface of the backing plate 6, and the outer edge of the second transition groove 66 is adjacent to the inner annular surface of the second stop 62, so as to smoothly transition the connection between the first stop 61 and the second stop 62 and the backing plate 6; The more dramatic the cross-sectional change is, the more obvious the stress concentration is. In order to reduce the stress concentration of the first stop 61 and the second stop 62 on the pad 6 and not interfere with the wheel 5, a first transition groove 65 and a second transition groove 66 are provided on the pad 6. The first transition groove 65 and the second transition groove 66 are adjacent to the first stop 61 and the second stop 62 respectively, and the connection between the first stop 61 and the second stop 62 and the pad 6 is smoothly transitioned, so as to reduce the stress concentration, reduce the stress amplitude, and improve the low cycle fatigue life of the first stop 61 and the second stop 62 on the pad 6, thereby reducing the test risk. Specifically, the cross-sections of the first transition groove 65 and the second transition groove 66 are both semicircular, so that the transition between the first stop 61 and the second stop 62 and the pad 6 is smoother, further reducing the stress concentration and the stress amplitude.

[0028] Specifically, Figure 2 As shown, the adapter 2 is divided into a first section, a second section and a third section from the second end to the first end, the diameters of the first section, the second section and the third section increase successively, and the axial height of the third section is less than the axial height of the pad 6, the diameter of the first section matches the diameter of the driving member 1 and is used to connect the driving member 1, the third section is interference fit with the second stop 62, the second section is a transition section between the first section and the third section, and the axial height of the third section is related to the mounting edge of the wheel disc 5 and the axial height of the pad 6 due to the limitation of the length of the bolt 3, and the axial height of the mounting edge of the wheel disc 5 is fixed, the larger the axial height of the third section, the smaller the axial height of the pad 6, and the fatigue risk points are mainly concentrated on the pad 6, so the axial height of the third section is less than the axial height of the pad 6, and the axial height of the pad 6 is increased as much as possible, which is beneficial to improving the ability of the pad 6 to bear centrifugal loads and axial bending loads, and the second section is used as a transition section between the first section and the third section to increase the centrifugal load bearing capacity of the third section.

[0029] Specifically, Figure 3As shown, the counterweight hole 21 is opened in the second section of the adapter 2. Opening the counterweight hole 21 in the adapter 2 avoids the superposition of tensile stress and centrifugal stress, so the stress amplitude is greatly reduced and the counterweight hole 21 is no longer a fatigue danger point.

[0030] A method for low-cycle fatigue testing of a bolted wheel disc, applicable to a low-cycle fatigue testing tool for a bolted wheel disc, comprises the following steps: S21, assembling the wheel 5; Heat the backing plate 6 to a set temperature, then fit the mounting edge of the wheel disc 5 into the first stop 61, fit the first end of the adapter 2 into the second stop 62, and align the bolt holes of the mounting edge of the wheel disc 5, the backing plate 6, and the first end of the adapter 2; S22, bolt 3 installation; After the backing plate 6 cools down, the bolt 3 is passed through the mounting edge of the wheel disc 5, the backing plate 6 and the bolt hole opened at the first end of the adapter 2, and the nut 4 is assembled and tightened; S23, test assessment; The second end of the adapter 2 is fixedly connected to the driving member 1, and torque is applied to the adapter 2 through the driving member 1, so that the wheel disc 5, the pad 6 and the adapter 2 rotate according to the set upper and lower limit speed spectrum. At the same time, the wheel disc 5 is heated to a set temperature through a heating device (not shown in the figure), and the pad 6 is replaced regularly according to the fatigue life of the pad 6 until the bolt hole part of the wheel disc 5 reaches the target fatigue life or reaches fatigue limit rupture.

[0031] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A low cycle fatigue test tool for a bolted wheel disc, used for performing a low cycle fatigue test on a bolt hole portion of a wheel disc (5), characterized in that: The invention comprises a driving member (1), a connecting portion (2) and a backing plate (6), wherein two axial ends of the connecting portion (2) are respectively a first end and a second end, a wheel disc (5) is mounted on the first end of the connecting portion (2) via the backing plate (6), and the second end of the connecting portion (2) is used to connect to the driving member (1) so as to output torque to the connecting portion (2) via the driving member (1); The two ends of the backing plate (6) in the axial direction are respectively provided with a first stopper (61) and a second stopper (62); the inner diameter of the first stopper (61) matches the diameter of the mounting edge of the wheel disc (5) for interference fit with the mounting edge of the wheel disc (5); the inner diameter of the second stopper (62) matches the diameter of the first end of the adapter portion (2) for interference fit with the first end of the adapter portion (2); The backing plate (6) and the first end of the adapter (2) are both provided with bolt hole portions corresponding to the positions of the bolt hole portions on the wheel disc (5), so that the bolts (3) can be installed to perform a low cycle fatigue test on the bolt hole portions provided on the installation side of the wheel disc (5).

2. The low cycle fatigue test fixture for bolted wheel disc according to claim 1, characterized in that: The axial height of the second stop (62) is obtained through finite element analysis, and the specific steps are as follows: S11, finite element model establishment; Establishing a finite element model of the adapter portion (2), the backing plate (6) and the wheel disc (5), and setting an initial axial height of the second stop (62); S12, structural finite element analysis; Applying centrifugal load and temperature load to the established finite element model to simulate the test state, and analyzing the stress level at the bolt hole position on the wheel disc (5); S13, stress level results analysis; If the stress level of the bolt hole portion on the wheel disc (5) is lower than the stress level of the bolt hole portion on the wheel disc (5) when the engine is in operation, it is determined that the bolt hole portion on the current wheel disc (5) is under-tested, the axial height of the second stop (62) is reduced, and the process returns to step S12; If the stress level of the bolt hole portion on the wheel disc (5) is greater than the stress level of the bolt hole portion on the wheel disc (5) when the engine is in operation, it is determined that the bolt hole portion on the current wheel disc (5) has passed the test, the axial height of the second stop (62) is increased, and the process returns to step S12; If the stress level of the bolt hole portion on the wheel disc (5) is consistent with the stress level of the bolt hole portion on the wheel disc (5) when the engine is in operation, it is determined that the current stress level of the bolt hole portion on the wheel disc (5) is qualified, and the current result is output.

3. The low cycle fatigue test fixture for bolted wheel disc according to claim 2, characterized in that: In step S13, if it is determined that the bolt hole position on the current wheel disc (5) is under-tested, the interference amount can be reduced based on the initial value of the interference amount between the second stop (62) and the first end of the adapter (2); if it is determined that the bolt hole position on the current wheel disc (5) is over-tested, the interference amount can be increased based on the initial value of the interference amount between the second stop (62) and the first end of the adapter (2).

4. The low cycle fatigue test fixture for bolted wheel disc according to claim 1, characterized in that: A first truncated cone (63) is provided on one side of the pad (6) where the first stopper (61) is provided. The diameter of the first truncated cone (63) is smaller than the inner diameter of the mounting edge of the wheel disc (5), and a smooth transition is formed between the edge and the pad (6).

5. The low cycle fatigue test fixture for bolted wheel disc according to claim 1, characterized in that: A second truncated cone (64) is provided on one side of the backing plate (6) where the second stopper (62) is provided. The radius of the second truncated cone (64) is smaller than the distance from the bolt hole on the backing plate (6) to the center axis of the backing plate (6), and a smooth transition is formed between the edge and the backing plate (6). A clearance groove for accommodating the second truncated cone (64) is provided on the end surface of the first end of the transition portion (2).

6. The low cycle fatigue test fixture for bolted wheel disc according to claim 1, characterized in that: The end faces of the two axial ends of the gasket (6) are respectively provided with an annular first transition groove (65) and a second transition groove (66); the first transition groove (65) and the first stop (61) are located on the same end face of the gasket (6) and the outer edge of the first transition groove (65) is adjacent to the inner ring surface of the first stop (61); the second transition groove (66) and the second stop (62) are located on the same end face of the gasket (6) and the outer edge of the second transition groove (66) is adjacent to the inner ring surface of the second stop (62), so as to smoothly transition the connection between the first stop (61) and the second stop (62) and the gasket (6).

7. The low cycle fatigue test fixture for bolted wheel disc according to claim 6, characterized in that: The cross-sections of the first transition groove (65) and the second transition groove (66) are both semicircular.

8. The low cycle fatigue test fixture for bolted wheel disc according to claim 1, characterized in that: The transition portion (2) is divided into a first section, a second section and a third section from the second end to the first end, the diameters of the first section, the second section and the third section increase in sequence, and the axial height of the third section is less than the axial height of the pad (6).

9. The low cycle fatigue test fixture for bolted wheel disc according to claim 8, characterized in that: The counterweight hole (21) is formed in the second section of the adapter portion (2).

10. A method for low cycle fatigue testing of a bolted wheel disc, applicable to the low cycle fatigue testing tool for a bolted wheel disc according to any one of claims 1 to 9, characterized in that: The steps include: S21, assembly of the wheel disc (5); The backing plate (6) is heated to a set temperature, and then the mounting edge of the wheel disc (5) is assembled into the first stopper (61), and the first end of the adapter portion (2) is assembled into the second stopper (62), and the bolt holes opened on the mounting edge of the wheel disc (5), the backing plate (6) and the first end of the adapter portion (2) are aligned; S22, bolt (3) installation; After the backing plate (6) has cooled, the bolt (3) is passed through the mounting edge of the wheel disc (5), the backing plate (6) and the bolt hole portion opened at the first end of the adapter (2), and the nut (4) is assembled and tightened; S23, test assessment; The second end of the adapter (2) is fixedly connected to the driving member (1), and a torque is applied to the adapter (2) through the driving member (1) so that the wheel disc (5), the pad (6) and the adapter (2) rotate according to a set upper and lower speed limit spectrum. At the same time, the wheel disc (5) is heated to a set temperature by a heating device, and the pad (6) is replaced regularly according to the fatigue life of the pad (6) until the bolt hole portion of the wheel disc (5) reaches a target fatigue life or reaches fatigue limit rupture.

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